Emiliano Martinez was Argentina's penalty shootout hero once more as they edged out Ecuador to reach the Copa America semi-finals, despite Lionel Messi's failed Panenka attempt.

The reigning champions survived a huge scare at NRG Stadium, where Kevin Rodriguez's stoppage-time equaliser cancelled out Lisandro Martinez's first-half header to take the last-eight tie the distance.

It appeared La Albiceleste's title defence was in doubt when Messi, back in the side after missing the Peru match with a hamstring injury, chipped the first penalty against the crossbar.

But Emiliano Martinez, who played a starring role from the spot during La Albiceleste's 2022 World Cup triumph, made saves to deny Angel Mena and Alan Minda, before Nicolas Otamendi struck the decisive kick for Lionel Scaloni's side.

Felix Sanchez's Ecuador had not scored in a Copa America quarter-final since 1997, but they made the brighter start in Houston.

Cristian Romero just about denied Moises Caicedo a shot on goal, before Emiliano Martinez came to Argentina's rescue as he blocked Jeremy Sarmiento's effort from a tight angle.

However, the reigning champions took the lead in the 35th minute when Alexis Mac Allister flicked Messi's corner towards the far post, where the unmarked Lisandro Martinez nodded into an empty net.

Ecuador were handed a gilt-edge opportunity to equalise from the penalty spot just after the hour mark, when Rodrigo De Paul was adjudged to have handled in the box.

However, they could not capitalise as Enner Valencia struck Emiliano Martinez's right post with his spot-kick, despite sending the Argentina goalkeeper the wrong way. 

But there was to be a dramatic late twist in stoppage time as Rodriguez glanced home John Yeboah's cross, with La Tricolor almost completing a sensational turnaround with Jordy Caicedo heading narrowly wide with the last kick of normal time.

They landed the first blow of the shootout when Messi's attempted Panenka clipped the top of the crossbar, but it proved a false dawn as Emiliano Martinez took centre stage yet again to swing the shootout back in Argentina's favour, before they scraped over the line.

Reigning champions scrape through by the skin of their teeth

Argentina are the first side through to the last four, and their title defence remains on track, but only just.

They broke the deadlock through Lisandro Martinez, who was in the right place to open his senior international account, while becoming the first Argentina defender to score in the Copa America since Victor Cuesta eight years ago.

Emiliano Martinez looked set to earn a fourth clean sheet of this tournament, and become the second Argentina goalkeeper after Sergio Romero to reach that tally in separate editions, but Rodriguez had other ideas with his dramatic equaliser.

Nevertheless, after Messi missed in yet another Copa America shootout - famously doing so in the 2016 final defeat to Chile - the goalkeeper dug his skipper out of a hole with two smart saves, eventually proving the difference.

Argentina hoodoo continues as Ecuador pay the penalty

Ecuador knew they needed to rewrite history to achieve a positive result here. La Tricolor had never beaten Argentina in the Copa America, losing 11 and drawing five of their 16 previous attempts, while they had won just five of the 40 meetings overall.

Despite conceding in the opening half for the first time in this tournament, they outshot their opponents (four to three) in the first 45 minutes, but the last of those efforts came in the 16th minute.

Though they snatched a dramatic equaliser, Valencia's earlier penalty miss was a sign of things to come, as the wait for a first semi-final appearance since 1993 goes on.

Nevertheless, Sanchez's side depart the United States having made history. Indeed, at just 17 years and 61 days old, rising star Kendry Paez became the youngest player to appear in a Copa America quarter-final.